Duality Symmetry and the Cardy Limit

We study supersymmetric and non-supersymmetric extremal black holes obtained in Type IIA string theory compactified on K3 X T^2, with duality group O(6,22,Z) X SL(2,Z). In the Cardy limit an internal circle combines with the AdS_2 component in the near horizon geometry to give a BTZ black hole whose entropy is given by the Cardy formula. We study black holes carrying D0-D4 and D0-D6 brane charges. We find, both in the supersymmetric and non-supersymmetric cases, that a generic set of charges cannot be brought to the Cardy limit using the duality symmetries. In the non-supersymmetric case, unlike the supersymmetric one, we find that when the charges are large, a small fractional change in them always allows the charges to be taken to the Cardy limit. These results could lead to a microscopic determination of the entropy for extremal non-supersymmetric black holes, including rotating cases like the extreme Kerr black hole in four dimensions.Comment: 46 pages, Latex, Some comments added in Introduction and Conclusions. Minor changes made in sections 3.4 and

Studies of expression in children’s free drawing and their response to aesthetic and other pictorial tests

The research aims at studying children's expression. It was, at the outset, restricted to the analytical study of free drawing; but subsequently its scope was enlarged through the following tests which the writer devised for the present study: (1) The Environment Preference Test. (2) The Projection Test. (3) The Visual Aesthetic Test. 1769 children aged 5-17 were asked to draw and paint pictures on the subjects which interested them most. This approach yielded the following results: l. The child records the images and impressions which loom large in a total situation in which he is the chief actor. 2. The environment a child depicts in his drawing represents his own environment (actual or idealised) which serves for an introduction to his field of activity. This indicates the frontiers of his world which he has been exploring and which is expressive of the dynamic aspect of his life space at his age. 3. The correlation between intelligence and artistic ability was found to be negligible (.02).The results of the pictorial tests supplemented these results and showed that children usually prefer pictures representing aspects of social activity, wholeness of the theme or familiar environment. Sex differences were noticeable among adolescents, girls excelling boys in visual aesthetic appreciation. Sex differences were not noticeable in children under the age of nine nor in adult art students. A small but positive correlation of .11 was found between visual aesthetic intelligence and general intelligence. Visual aesthetic intelligence and artistic ability showed a correlation of .10. The educational and psychological implications of the results seem to be significant in that these tests reveal the centres of interest for the child in terms of environment and activity which may be useful in formulating principles of curriculum-making. They also reveal the need for guiding those children who lack social stimulus

Time Dependent Cosmologies and Their Duals

We construct a family of solutions in IIB supergravity theory. These are time dependent or depend on a light-like coordinate and can be thought of as deformations of AdS_5 x S^5. Several of the solutions have singularities. The light-like solutions preserve 8 supersymmetries. We argue that these solutions are dual to the N=4 gauge theory in a 3+1 dimensional spacetime with a metric and a gauge coupling that is varying with time or the light-like direction respectively. This identification allows us to map the question of singularity resolution to the dual gauge theory.Comment: 13 pages REVTeX and AMSLaTeX. v2: corrected typos and made some clarifications; reference added; v3: more clarifications, references adde

Duality Symmetry and the Cardy Limit

We study supersymmetric and non-supersymmetric extremal black holes obtained in Type IIA string theory compactified on K3 X T^2, with duality group O(6,22,Z) X SL(2,Z). In the Cardy limit an internal circle combines with the AdS_2 component in the near horizon geometry to give a BTZ black hole whose entropy is given by the Cardy formula. We study black holes carrying D0-D4 and D0-D6 brane charges. We find, both in the supersymmetric and non-supersymmetric cases, that a generic set of charges cannot be brought to the Cardy limit using the duality symmetries. In the non-supersymmetric case, unlike the supersymmetric one, we find that when the charges are large, a small fractional change in them always allows the charges to be taken to the Cardy limit. These results could lead to a microscopic determination of the entropy for extremal non-supersymmetric black holes, including rotating cases like the extreme Kerr black hole in four dimensions.Comment: 46 pages, Latex, Some comments added in Introduction and Conclusions. Minor changes made in sections 3.4 and

Immediate postpartum IUD: analysis of factors making it contraceptive of choice

Background: Intrauterine devices are convenient, long term, reversible means of contraceptive. They are user friendly due to one-time application, ease of removal and immediate return of fertility on its removal. The Immediate Postpartum IUD is inserted in women within 48 hours, after normal delivery. The study aims to understand factors responsible for making IUD as the contraceptive of choice. It also identifies various social, demographic factors responsible for making IUD as the contraceptive of choice.Methods: A cross-sectional observational study was done using pretested questionnaire. In total 470 subjects were interviewed. The data were collected and compiled using MS-excel and analyzed by using Epi info-7. Data is presented in terms of proportions.Results: The acceptance of IUD as a contraceptive was not statistically associated with age & income of the user. Acceptance for IUD increased with literacy (P = 0.003). Almost 77.8% users were satisfied by the IUD. In total, 66.68% users, who continued using IUD did not feel any discomfort. The compliance of IUD was significantly associated with the discomfort caused (P = 0.0008) which was found to be most important reason for its removal. The commonest reason for adoption of IUD was a long duration of its use. It was seen that 23.40% previous contraceptive users and 39.41% new IUD users accepted it as contraceptive. Its acceptance is especially more in previous IUD users.Conclusions: Immediate post-partum IUCD has high acceptability and more than 75% users are satisfied and consider it as a contraceptive option.